How to Model a Keyboard key?
In short, start from a cube. (in the gif I have a mirror modifier to save time)
Delete the bottom face.
Add loop cuts for the rounded top.
Position the top correctly, by simply G grabing, and R rotating and S sclaing the top geometry.
Use proportional editing O to create the dip in the top.
CtrlB to bevel the vertical sides.
(optional) Remove the Ngons in the top, that beveling the sides created.
Bevel the top ridge to make it smother and more realistic.